Effectiveness of water treatment for the removal of Cryptosporidium and Giardia spp

• Published in: Epidemiology and infection 2012-11, Vol.140 (11), p.2014-2022
• Main Authors: BAJER, A., TOCZYLOWSKA, B., BEDNARSKA, M., SINSKI, E.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cryptosporidiosis - prevention & control; Cryptosporidium; Cryptosporidium - genetics; Cryptosporidium - isolation & purification; Cysts; DNA, Protozoan; Drinking water; Drinking Water - parasitology; Fluorescent Antibody Technique; Foodborne illnesses; Fundamental and applied biological sciences. Psychology; Giardia; Giardia - genetics; Giardia - isolation & purification; Giardiasis - prevention & control; Humans; Infections; Intestinal infections; Laboratories; Likelihood Functions; Microbiology; Models, Statistical; Oocysts; Parasites; Parasitology; Performance evaluation; Poland; Polymerase Chain Reaction; Protozoa; Sediments; Surface water; Tap water; Water pollution; Water Purification; Water Quality; Water samples; Water treatment; Water treatment plants
• ISSN: 0950-2688; 1469-4409
• DOI: 10.1017/S0950268811002780

Cryptosporidium and Giardia are intestinal parasites of humans and of many other species of animals. Water constitutes an important route of transmission for human infections in both developed and developing countries. In Poland, contamination of water sources with oocysts/cysts is not routinely monitored and scientific research in this field is scarce. Our aim was to compare the contamination of surface and treated water and thus the success of water treatment processes. Water samples (n=94) of between 30 l (surface water) to over 1000 l for tap water, were taken in the period of 2008–2009 using specially constructed equipment with cartridge filtration (Filta-Max; IDEXX, USA). Immunofluorescent assay, and nested polymerase chain reaction were used for the detection of parasites. Cryptosporidium oocysts were found in 85% of surface water and in 59% of raw (intake) water samples. Oocysts were also detected in treated water (16%) but were absent in samples of swimming pool water. The highest mean number of Cryptosporidium oocysts [geometric mean (GM)=61/10 l] was found in samples of rinsing water. Giardia cysts were observed in 61% of surface water samples, in 6% of raw water and in 19% of treated water, with the highest number of cysts noted in rinsing water samples (GM=70 cysts/10 l). Our study highlights the frequent occurrence of parasites in surface waters in Poland and the effectiveness of water treatment for the removal of parasites from drinking water.